Spark plug



1,523,069 R. H UG H ES SPARK PLUG Filed Nov. 6, 1923 IN VEN TORATTORNEYS Flt:

Patents Jan. 13, 1925. I

ROBERT HUGHES, OF COLUMBUS, OHIO.

SPARK PLUG.

Application filed November 6, 1923. Serial No. 673,154.

To all whom it may concern.

Be it. known that I, ROBERT Hnonns, a citizen of the United States ofAmerica. and resident of Columbus, in the county of Franklin and Stateof Ohio, have invented certain new and useful Improvements in SparkPlugs. of which the following is a specification.

This invention relates to spark plugs adapted for use in internalcombustion engines and has for its object the provislon of a devicewhich will produce a plurality of sparks in timed relation With thefiring stroke of an engine.

Another object of the invention is the provision of a device forproducing a plurality of sparks in the circuit of that portion of aspark plug which is adapted to be projected into the combustion chamberof an engine.

The invention further contemplates the use of an element forming anintermediary between the terminals of a spark plug for producing aplurality of distinct and independent spark gaps whereby secondarysparks produced between the intermedlary and the ground element of theplug are greatly intensified. I

A still further object of the inventlon IS the provision of a spark plughaving a plurality of spark gaps and in which the construction of theelements forming the gaps is of a rigid nature that the plug may bereadily cleaned without readily disturbing the adjustment of the points.

Other objects and advantages will be apparent during the course of thefollowing description.

In the accompanying drawing forming a part of this application and inwhich like numerals are employed to designate like parts throughout thesame,

Figure 1 is an elevation of a partly in section,

Figure 2 is an elevation of a spark plug constructed according to myinvention,

Figure 3 is a. horizontal section of my plug disclosing an intermediatemember for causing a plurality of sparks.

Figure 4 is a view 1n perspective of a blank from which the intermediatemember is formed.

Referring more particularly to the drawing. 1 designates a threaded bodyor metal shell adapted to be screwed into the usual threaded opening inthe cylinder head of an engine and forming the ground connection sparkplug or one of the terminals of the plug. A orcelain 2 is provided withthe usual shoul ers for supporting and maintaining the porcelain withinthe body 1 when the several members of the plug have been assembled. Theporcelain has an exposed portion 3 extending beyond the shell 1 toreceive a packing gland nut 4. This nut is screwed upon a threadedreduced end of the shell and seals the shell against the escape of gasesfrom the cylinders of the engine and also looks the plorlclelain againstdisplacement from said S18 The portion 5 of the porcelain which normallyis located in the combustion chamber of the engine is spaced from theinner wall of the shell 1 and is provided with a recess 6 into which isfitted the stem of a porcelain plug or insulating clamping member 7.Said member is provided with a shoulder 8 for a purpose which will bepresently explained.

A central passage is formed longitudinally of the porcelain 2 and theclamping member 7 through which is inserted a terminal or electrode 9having a slotted head 10 at its inner end and a threaded portion 11 atits outer end, upon which portion is screwed a binding nut 12 forlocking the usual terminal of an ignition wire to an assembly nut 13.The nut is locked against a washer 14 which is in engagement with theupper end of the porcelain 2.

Between the lower recessed end of the porcelain 2 and the shoulder 8 ofthe clamping member 7 there is positioned an S-shaped plate orintermediate electrode 15 having a central perforation 16 through whichis inserted the plug 7. The plate is provided with concentric arms 17and 18. The free ends of the arms are bent in opposite directions toform respectively sparking electrode points 19 and 20. Electrode 19 ispositioned to form a primary spark gap between a disk 21 clamped to theouter end of the shoulder 8 of the insulating member 7 by the head 10 ofthe conductor 9. The other electrode is located .in spaced relation withthe lower end of the metal shell to form a secondary spark gap betweenthe plate 15 and said shell.

en a current is passed through the conductor 9 in the usual manner, aspark will be formed at the gap between and the electrode 19 spaced fromsaid disk, and a secondary spark of greater intensity will be producedat the gap between the electhe disk 21 since the distance betweentheears and the plate is adequate to permit the oil to escape. Themultiplicity of gaps in series create an intensity of sparking whichwill readily burn away oil thrown upon the points.

While I have shown two sparking electrodes, any number suitable for thepurpose may be employed, in'spaced relation with both the disk 21 andthe lower end of the shell 1.

The plate 15 is made of someform of conducting metal and is insulatedfrom the stem or conductor 9 by the insulating clamping member 7, and istherefore in series with the ignition circuit of the spark plug.

The metal of plate 15 is of such a character that the arms 17 and 18 maybe bent at will in order to adjust their respective points 19 and 20when necessary to maintain the proper spacing between said points andthe adjacent conductors for producing efficient sparks. I

I claim 1. A spark lug comprising a metal shell, :1 central conductorprovided with a head at one end, a porcelain insulating the conductorfrom the shell and provided with a recess at its lower end, aninsulating clamping member seated within the recess and provided with ashoulder, a metal plate having concentric lateral arms and clampedbetween one end of the porcelain and the shoulder of the insulatingmember, a metal disk secured'on the outer end of the clampmg member bythe head on the central conductor, the ends of the arms of the platebeing bent in opposite directions and spaced respectively from the diskand inner end of the shell.

2. A s ark lug comprisin a metal shell, a centre con uctor, a porce aininsulating the conductor from the shell and PYU aided wlth a recess atits lower end, an insulating clamping member seated within the recess, ametal plate having concentric lateral arms and clamped between one endof the porcelain and the insulating member, a metal disc secured to theouter end of the clamping member and in contact with the centralconductor, the ends of the arms of the plate being bent in oppositedirections and spaced respectively from the disc to the inner end of theshell.

3. In a spark plug having a metal shel an electrode, and a porcelaininsulating the electrode from the shell, an intermediate conductor,means for insulating the conductor from the electrode and for clampingsaid conductor to'the porcelain, a disc clamped to the insulating meansand in contact with the electrode, said conductor being provided witharms at diametrically opposite points, the end of one arm being spacedfrom the disc, the end of the other arm being oppositely directed fromthe first mentioned arm and having an end spaced from the shell to formspark gaps in series with the circuit of the plug, said arms beinglocated within a peripheral edge of the disc and lower end of the shell.

- ROBERT HUGHES.

